STANLEY WOODS’ CRITTERS: Spotted Banana Slug 

Spotted Banana Slug
Ariolimax columbianus

Spotted Banana Slug with debris-laden slime at its tail.

genus: Ariolimax  species: columbianus.

A. columbianus lives as far north as Sitka Alaska, west of the Cascade range in British Columbia, Washington and Oregon; into California as far south as the Salinas Valley. This is the only species that is sometimes spotted and has great colour variations.

The Banana Slug was first given a scientific name in 1851 by Augustus Gould. Columbianus is named after the Columbia River district where this animal was first studied. Extensive research on these Ariolimax species was published by Albert Meade in 1943.

Banana Slugs are the largest of all North American slugs. Most adult Ariolimax slugs are about 15 - 20 cm (six to eight inches) in length. They can reach a length of 25.4 cm (10 inces). They are the second largest slug in the world, the largest being the Limax cinereoniger of Europe, which can reach 30 cm (12 inches) in length.

Banana Slugs eat living and decaying vegetation, roots, fruit, seeds, bulbs, lichen, algae, fungi, animal droppings and even carcasses. Mushrooms are their favourite food. Predators include snakes, foxes, porcupines, crows, ducks, shrews, moles, salamanders and even humans.

Banana Slugs are hermaphrodites. Each animal has both male and female reproductive organs. Banana slugs mate with each other at all times of year, and they usually cross-fertilize, each producing eggs and sperm simultaneously. The mating ritual may last more than 12 hours, often spent pulling and twisting into incredible positions as they try to pull apart. Often, the penis of one of them must be gnawed off in order to release the pair. This unique phenomenon is known as apophallation.

References:
Funk & Wagnalls Wildlife Encyclopedia 18. Funk & Wagnalls, Inc. New York, NY, 1969/1970.
The Banana Slug: A Close Look at a Giant Forest Slug of Western North America. Written By Alice Bryant Harper; photos by Daniel Harper, 1988.

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(Four-colour plates prepared and printed by Dai Nippon Printing Company, Ltd. Tokyo, Japan.)